Tone, with your gasifier, when it is powered by perfectly dried wood, do you produce dry gas? (like the gas from a coal gasifier with a downward flow)
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"The biggest difference is in the size of the air nozzles, and I think this is essential. If we make an experiment and blow compressed air into the embers through a small hole, we can see that this method ignites the charcoal much more than a gentle breeze, and I also believe that in the first case, much less air is introduced. I think that the narrow and fast jet of air also drags and swirls the pyrolysis gases, which penetrate deep between the glowing coals and thus the conversion of gases takes place at a high temperature. "
Do you mean that the air must not only enter at high speed into the gasifier but also through many small holes?
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Bob answered the question perfectly. Charcoal has too litle water, wood too much. Thats why l developed what Bob later baptised as Rocked fuel. Your torrefied wood achives the same thing! The thing is, even wood with 0% moisture (technicly impossible) still has one molecule of water too much per atom of carbon, so either we chemicaly eliminate water (torefication) or add carbon to it (charcoal).
Yes, l have observed and writen about this âsupernovaâ effect a lot in my Mercedes thread. Indeed, once the gasifier gets to a certain temperature, interesting things start to apear. You wuld think that the gasifier wuld go to heater mode, spiting unreduced gas trugh the grate, but not in my experiance. I once tryed flooring it on the highway for a long time. Imagine. A 2.3l engine, with a gasifier l belive 7" in size. Runing on either Rocket fuel or wet charcoal, cant remember, doing over 85mph and still wanting to go higher but the traffic was bad. It just seemed it had limitless gas producing capability!
But! Whem l opened the gasifier next day, instead of a charcoal filled charbed, inside was a ball of slag the size of a large grapefruit 
and the gasifier cracked badlyâŠ
So. First of all. To reach those temperatures, raw wood is out of the question. There just is no way, its water moderates heat too well. So torrefied wood or Rocket fuel, or wet char. Mercedes also had a excelent gas heat recovery heatex.
Second, we must ask ourself do we realy want this effect? Deal with slag and half molten gasifier? I dont knowâŠ
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I think that it is impossible to get such caloric gas in a charcoal gasifier as from a wood gasifier. For example, when we open the lid on the wood gasifier and brown smoke rises from it, which is created from dried wood, we all know that this is a terribly strong gas, but greasy, full of tar, but when this gas passes the hot zone and is blown by air jets pushed deep into the glowing coals, the gas we want is created. A construction that would enable such operation in a wide area is a challenge for me. I have before my eyes a sentence uttered by my brother PrimoĆŸ, âsteam and pyrolysis gases must be pushed into the heart of the actionâ, so a narrow and fast jet of air would be the right solution, as it moves the extreme heat away from the housing and metals and pushes it there and vortices of pyrolysis gases. In this way, the extreme heat stays in the middle of the hot pipe, where a loose zone is created, here the pieces of coal and hot gases swirl without problems and move downwards, but here the air jets tear them apart and push them aside,⊠It would be very good if the gasifier would work in overpressure, this would be achieved by blowing air onto the nozzles, the condensation of water vapor would be much more efficient, but there is a great risk of gases coming out, so I am abandoning this idea, but in the future I will try using even smaller air openings
Thierry, lately Iâve been using exclusively air-dried wood that dries in the gasifier, I can say that there is no water leakage from the front of the refrigerator, well, the filter is still a bit damp
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Tone I believe you are on the right track, since Joni came to the same conclusion with his gasifier. High velocity nozzles with a significant length to build a self repairing protective ash layer.
In my WK that I am building I think I may have accidentally jetted my nozzles. The lug nut nozzles I added are 1/2" but before the nozzle are 3/4" holes. May create a Venturi effect. Iâve been wondering if that would be detrimental to the way a WK naturally works.
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Yes Tone.
You re-state one of many reasons to pursue raw wood gasification.
A challenge without a doubt.
Rise to this challenge. For the net energy benefits.
I live in a place of mountains, small plains valleys and the mighty ocean. A place where it annual does rain a lot.
So flowing rivers. Many, many flowing rivers small to mighty.
The WK system is one of the lower Columbia River dams. Not all that high. By retaining and channeling a relatively slow flow; but a massive volume of flow. Flows capable of filling valley plains with deep, deep rich silt. Create wash out deltas into the ocean. Flow volumes harnessed, able to powering whole cities and industries.
The air velocity is king gasifier systems are like one of the upper Columbia River power dams. Up there less flow volumes but falling from higher that flow/velocity churning does easily carry down all fines and silts and erode away first soft, and then hard rocks making fresh minerals available. Dam restrained and channeled makeing useable power too.
There are selected uses and needs for charcoal gasifier systems. But it is offensive to see the energy loss in the charcoal making part of it to me and others. Impossible to justify this except as a narrow needs solution.
A fancy sweet cake to be eaten occasionally.
Much better to daily live on full use soups and stews. Meat pies.
CodyT reminded of Joni who did develop and demonstrate good power from chipped type wood fuels.
There was in the early 2000âs related an account of the modern Finnish woodgas driver who on his very complex W flow pathway hearth had a burn through introducing wood chip pyrolysis gasses directly deep into hot active hearth core.
He was then getting wonderful engine power. He could not explain the whyâs of this.
He did then however supposedly intentionally designed to duplicate this.
He held the information close, hoping to patent it and sell to the big power companies I think. Or maybe unwilling to share until he could explain the why of it.
Your concept has been discovered and done previously Tone.
Keep pursuing this.
Best Regards
Steve Unruh
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I have found the size of the holes in the nozzle and how many nozzles to the size of the engine are directly related, the engineâs rpm, that makes vaccum makes the velocities of air being pulled into the firetube through the nozzles. On the other hand same size liter engine the vaccum can very greaty by rmps of the engine. Adding a active charbed of a hot
Lobe high heat will change it more.
Try this some time with a cold firetube. Look at the vaccum measurements above the charbed hopper reading and after the charbed your cooling rail readings driving. Running all the air through the gasifier system to the engine on gasoline or diesel vs. running the same engine with the gasifier operating with a hot active Charcoal bed. The nozzles velocities of air flow are the same moving through with the same rpms right? No. But the vacuum pull readings will be much lower. Why? It is the cold gasifier Charcoal bed. High vaccum or high low velocities are not just the size of the holes or how many you have. It can be your charbed being what we call loose or tight. Lots of variables in a gasifier of different types of design in the firetube. Some with insulation and layers with ash, some designed to pull heat out of the firetube transfering to the in coming air that protects the fire tube metals. The list goes on and on.
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Harder, but not impossible 
charcoal has all the potential to make gas with a consistancy of 50% CO and 50% H2 (water gas), without the danger of tar ruining the sistem like wood does. Geting to that is a nother question⊠sometimes it happens. Like from all the guys reporting extreme power when low on wood. Or the anecdote l wrote with my Mercedes on the highway. But to put this to everyday use is a nother questionâŠ
This water gas is what can be seen as a flame at gasifiers air intake at shutdown, when steam reacts with hot carbon and makes this potent nitrogen free gas. This gas is stupid fast burning, and l dare to say probably shuld be stronger thain petrol.
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I am not sure that it got clear on in the text, I read it a few times and interpreted it different the second time around (which is probably how you meant it) so this is just to make sure for me and other newbies. 
As you all know I donât have any actual experience yet but the big increase in volume and velocity because of the heated air/gas should cause very different readings.
But this is a smart way to identify if you have bottlenecks in the system, especially if you have many points to read the vacuum by moving the meters to get the vacuum difference between different parts of the gasifier.
If they show on a cold system then also have unnecessary vacuum when running the gasifier as well.
And please tell me if I am wrong so I can learn 
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Very true. A dead cold charbed doesnât offer much resistance at all. Even whith the gasifier lit I find the vacuum ratio can sometimes double with a long hard pull vs moderate speeds.
In the back of my mind I seem to remember at some point we discussed the fact that air expands about 3 times with a 300C increase (negative pressure not taken into account). Imagine what will happen to the gasses passing the live char.
An interesting experiment would be to somehow compare the woodgas flow exiting the gasifier vs downstream the cooler. Maybe weâre underestimating the tubing size needed for the hot parts.
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That is kind of how I am thinking too, up the hot dimensions to keep the resistance as low as possible
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Somewhere i described my Volvo system, i put on piping like my mentor told me, double cyclones, from them 2x2 1/2" down to one 3" pipe over the back, on the roof down to 2 1/2" pipe down front to the filters, after filters 2" pipe up to engine. No cooler on this, gas around 40°c always up engine (up 50°c hot summer).
He learned me about the gas expansion law, donât remember now, gas heated from 0° to 275° expands 5 times?
This should help keep gas speed steady along the piping.
On the chevy i just use too big pipes all the way, because there is space, and i had them.
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Thatâs good information Göran. I wonder if Iâm ever going to get to the point where I can quote Wayne and say: - âI donât know of anything I would do differentlyâ
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I cannot contribute much at the level you guys are now talking except some observations that Iâve seen.
In the hot active char bed the char chunks will âfluffâ separate. Even set up a frequency jumping apart depending on the actual temperature level driven up too, and the forced induced gasses drawn through.
So all cold flows calculations are just a convenience, starting, reference point.
Other real factors of char particles like pillow-fracturing determined by origin species; ashing; gas temperature expansion; etc. will rule down in the hearth core.
Gasses flow through filtering particle stacks tend to compact the particles increasing the flow resistances. Non-outgassing particles do not fluff separate increasing the interstitial flow possibilities. They pack stack.
S.U.
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I think (always dangerous) for gas expansion, absolute temperature is what you need, that is, Kelvin, K. So add 273 degrees to get from C to K, and 0 to 275C becomes 273 to 548K, and the volume doubles. A factor of two is pretty easy to remember, probably why your mentor chose it. If the pressure changes also, things would change, but a factor of 2 for pressure in a gasifier seems unlikely, so less change because of pressure.
Who knows? I might even be right 
,
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Dutch John has a formula up on his site to get a good ballpark for your hot gas piping size, before the cooler. As it gets more cool and dense you can go smaller. No such thing as too wide, but as you run smaller you risk being restrictive and dropping soot from the turbulent flow.
https://www.woodgas.nl/GB/diy.html
I think he includes a Kelvin formula as well.
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If we talk about negative pressure or different pressure conditions in the gasifier, we have to remember the operation of the carburetor for gasoline, narrowings, various holes in certain areas that serve to prepare the fuel/air mixture. The operation of the carburettor is based on vacuum, which sucks fuel through precisely drilled openings in certain areas at the throttle valve and in the venturi tube. At first glance, it looks very simple, but there is a science in the details. With the gasifier, the thing is similar, well, here I have to repeat Kristjanâs words: âwe have to imagine the gasifier filled with fuelâ. If I continue thinking about the pressure conditions, I can start at the grille, where the negative pressure is always the greatest, because from here the engine âdrawsâ gases freely. I wrote incorrectly that the engine âpullsâ gas, because gas or liquid cannot be pulled, we can pull a rope or chain, but gas or liquid can only be pushed, or rather, the flow of gas or liquid goes from a higher pressure to a lower one. The air inlet pressure at the air openings is determined by the ambient pressure, and the pressure inside the gasifier is primarily influenced by the pressure created by the engine with its gas consumption, so we can easily see that the air almost constantly penetrates the openings closer to the exit, the higher ones openings begin to enter when gas consumption increases. I say this because we must not forget the expansion of gases, which are created due to hot radiation and the rise of extremely hot gases in the middle, and this conversion of solid matter into gases raises the pressure inside. It would be interesting to know what the ratio is between the amount of fresh air that enters the process to cover heat losses and the amount of gas produced. An ideal, heated gasifier for dry wood should work almost without the addition of fresh air, but in reality we have a lot of heat losses, which we cover by burning wood, that means additional excess water and nitrogen in the gas.
I can already see that Iâm babbling and philosophizing, so Iâll conclude by just saying that with the gasifier on the tractor, the total cross-section of the air intake openings represents the cross-section of the pipe 1/2" and thatâs more than enough for a power of 20 kW.
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Yes , I did not go all the way into it with gasifier systems. It can get complicated. Like the problem of blocked lower piping were water gets traped the gases have to go through a bubbler pipe. Or the hayfilter is the problem resticting the gases flow to the engine. Air leaks into the Gasifier system too. It can really make you go around in circles trying to figure problems out. Multiple problems combining making one big problem.
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Not babble at all Tone.
Drawn flow can never be more the the weight/mass of atmosphere doing the pushing.
However a gasifier internally produces gaseous heat expansion and gases made pressure. Gets complicated.
Also as you had said earlier it is not so hard to mildly pressure air-in feed the gasifier system.
Not commonly done for CO leakage safety.
Not so commonly done and then lose the easy engine variable draw demand.
An external, especially vehicle system pressurized CO hazards can be open ventilated accepted. Maybe. Ha! People still smoke tobacco and more and more weed. Vape.
I still insist and enjoy in-house, in-room stove wood heating.
My wife still loves her mildly scented in-house candles. Sigh.
We accept living higher levels of CO2 and maybe at times even a little of CO.
Fear of parts per million will Life shorten you too. All extreme controlling fears will stressâs kill you.
The newest vehicle gasoline fuel injected systems do now use variable driven fuel pressurizing pumps. Pressure sensor feed back controlled. Pressure boosted for acceleration assistance and max loading power with controller mapped programing.
So, now, today; variable electric blower gasifier inlets down to the DIY level are very possible.
Not my cupâo tea for sure. I like my teas simple; black cured; and strong brewed.
But others will see the way to variable low pressure feed gasifiers.
Beginning with a human hand on the controller knob.
Regards
Steve Unruh
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One of the biggest killers of the human race fears and stresses. Being at peace in life is very healthy.
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